SELENITE BROTH

Technical Data #2815a / 2013.07.02

Selenite Broth is a selective enrichment medium used for cultivation of Salmonella and some Shigella sp. Specimens from feces, urine, water and foods may be inoculated even if quantity is very low. Sodium selenite inhibits gram-positive cocci as enterococci and gram-negative bacteria as coliforms.

 


 

FORMULA
in grams per liter purified filtered water

Casein/Meat Peptone

5,0

Lactose

4,0

Sodium Selenite

4,0

Sodium Phosphate

10,0

pH 7.0 +/- 0,2 à 25º C

This approximate formula may be adjusted and/or enriched to obtain best results.


PRECAUTIONS
This medium is for IN VITRO diagnostic use only.


STORAGE
Store prepared media at 2-8º C protected from direct light and dehydrated powder, in a dry place, in tightly-sealed containers at 2-25º C.


SIGN OF DETERIORATION
Media should not be used if the expiry date has passed. Prepared media should not be used if there are signs of contamination or deterioration (shrinking, cracking, evaporation or discoloration, or if red color appears). Do not use dehydrated media if it is caked or if an orange color is developped after container is opened.


DIRECTIONS
Suspend 23 g of dehydrated media in 1000 ml of purified filtered water. Heat with frequent agitation and boil for one minute. DO NOT STERILIZE. Cool to 45-50º C. Mix gently and dispense into sterile culture tubes.


PROCEDURE
Prior to inoculate, the prepared media should be brought to room temperature.

  1. Inoculate tubes with specimens. Stools should be emulsified into the broth before incubation.
  2. Incubate at 35º C for 24 hours with loosened caps.
  3. Subculture a few drops onto selective media for isolation of pathogens. Incubate at 35º C for another 24 hours.


QUALITY CONTROL

Results after 24 hrs at 35ºC

Organisms

ATCC

Growth

Shigella sonnei

9290

+ or partial inhibition

Salmonella typhimurium

14028

+

Escherichia coli

25922

- or partial


LIMITATIONS OF METHOD
Do not incubate broth longer than 24 hours. This medium is only a part of the identification. Other tests may be required.


REFERENCES

  1. Lennette, E.H., A. Balows, W.J. Hausler Jr., H.J. Shadomy 1985 Manual of Clinical Microbiology 4th ed. American Society for Microbiology, Washington, D.C.
  2. Mac Faddin, Jean F., 1985 Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria. Vol.1. Baltimore, MD.: Williams & Wilkins.
  3. NCCLS 1990 Quality Assurance for Commercially Prepared Microbiological Culture Media Approved Standard Document M22-A Vol.10, No.14
  4. Taylor, W.I., B. Harris 1965 Isolation of Shigellae Comparaison of plating media and enrichment broths. Am. J. Clin. Pathol. 44:476-479


CATALOGUE NUMBERS

Dehydrated media 500 g QB-39-3810
     
Prepared media    
Tubes, 16x125 mm 10/pkg 2815

 


 

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